Generally, a secondary battery may be rechargeable and have increased capacity. A representative example of the secondary battery includes a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, and the like. Among them, the lithium ion battery has been spotlighted as the next generation power source due to excellent characteristics such as a long lifespan, high capacity, and the like. Among them, a lithium secondary battery, which has operating voltage of 3.6 V or more, is used as a power supply of a portable electronic device or several lithium secondary batteries are connected in series with each other to thereby be used for a high output hybrid vehicle. Since this lithium secondary battery has operating voltage three times higher than that of the nickel-cadmium battery or the nickel-metal hydride battery and is more excellent in view of energy density characteristics per unit weight than the nickel-cadmium battery or the nickel-metal hydride battery, the use of the lithium secondary battery has rapidly increased.
The lithium secondary battery may be manufactured in various types. A representative type of the lithium secondary battery may include a cylindrical type and a prismatic type that are mainly used for the lithium ion battery. A lithium polymer battery that has been recently spotlighted is manufactured in a pouch type having flexibility, such that it has a relatively free shape. In addition, the lithium polymer battery has excellent stability and light weight, such that it is advantageous for slimness and lightness of the portable electronic device.
Meanwhile, in a case of a power source for driving a motor of an electric automobile, or the like requiring a large amount of power, several tens of secondary battery cells are connected in series or parallel with each other to thereby configure a battery module.
When a plurality of battery modules are charged or discharged, heat is generated from the cell and charging or discharging performance of the battery cell may be varied depending on a temperature of the cell.
Therefore, it is important to maintain an internal temperature of the battery at appropriate temperature.
A secondary battery module disclosed in Korean Patent Laid-Open Publication No. 2007-0014631 according to the related art includes a plurality of unit cells which are stacked and arranged to efficiently cool heat generated from the unit cell, and a plurality of partitions installed between the unit cells and having a cooling passage formed therein and protrusions formed on both surfaces thereof.
Therefore, the related art relates to a method of cooling the cell while a heat transferring medium is circulated in the plurality of partitions.
However, since the related art has the passage formed in the plurality of partitions, it has a complicated structure, such that the circulation of the heat transferring medium is not smooth.
In addition, since the secondary battery module according to the related art has the complicated structure, it is difficult to manufacture.